Is brine an effective solution for icy streets?

EXPLAIN IT TO ME

A truck treats a road in Hampton, Va., with a brine solution to help prevent… (Adrin Snider, Tribune Newspapers…)

February 22, 2011|By Dan Hartzell, OF THE MORNING CALL

Q: What exactly does the brine applied to streets for melting snow and ice consist of? Is it simply salt water, or is something else added? Why use brine instead of salt in solid form? Are better substances for melting snow and ice available and in use?

A: It seems like a no-brainer that road salt, and its liquid relative known as brine, are reasonably effective in preventing the buildup of snow and ice on roadways. Anyone who's thrown salt crystals marketed for that purpose onto the driveway or sidewalk can attest that lanes of wet surface surround the salted areas, which in turn are flanked by snow.

So the stuff works, up to a point. Sodium chloride lowers the freezing point of water, but only from 32 degrees Fahrenheit to 20 or 18 degrees. Other chemicals are more effective — magnesium chloride works down to the 15- to 13-degree range — but also more expensive, and some of them can be more corrosive than salt.

Generally, brine (simply salt and water) is used in advance of a predicted storm to help prevent the buildup of snow or ice. In that function, brine works better than dry salt crystals because the thin coating of salt it leaves after it dries adheres to the road surface more effectively. On bare roads, traffic throws salt crystals to the edges or even off the road more easily.

In many of the state's de-icing operations today, brine is sprayed onto the dry salt crystals as they are being applied to the roads during storms as well, to give the crystals a boost, said Transportation Department spokesman Steve Chizmar. "Salt has to go into solution to work best," he said.

Even on lower-volume roads where dry salt alone is applied, cinders often are added to increase traction — not only to keep vehicles moving along, but to create friction, and thus heat, melting snow and ice and adding water to the mix in that manner, Chizmar said.

Newer organic compounds are being marketed as well, in part for their green credentials. PennDOT has been testing a solution derived from red beets, and though it seems to be effective, no decision has been made on making vegetarian de-icer a regular component of the state's overall treatment regimen.

"It's still being piloted," Chizmar said, as in "pilot project."

Before we sign on to the green benefits of red-beet brine, it's important to know that, like the more exotic chemicals, the earth-friendly option can cost 10 times as much as brine — about $3 per gallon versus less than 30 cents. That might prompt even Al Gore to ease off the accelerator.

— Dan Hartzell, The Morning Call

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